sql中的IMPLICIT JOIN的目的是什么? [英] What's the purpose of an IMPLICIT JOIN in sql?

问题描述

因此，我不太了解在SQL中使用隐式连接的目的.我认为，这使联接在代码中更难发现，我对此很奇怪:

So, I don't really understand the purpose of using an implicit join in SQL. In my opinion, it makes a join more difficult to spot in the code, and I'm wondering this:

除了简单之外，是否真的有更大的目的要做?

Is there a greater purpose for actually wanting to do this besides the simplicity of it?

推荐答案

根本上，隐式联接和显式JOIN .. ON之间没有区别.执行计划是相同的.

Fundamentally there is no difference between the implicit join and the explicit JOIN .. ON. Execution plans are the same.

我更喜欢显式表示法，因为它使阅读和调试更加容易.此外，在显式表示法中，您定义ON子句中的表与WHERE子句中的搜索条件之间的关系.

I prefer the explicit notation as it makes it easier to read and debug. Moreover, in the explicit notation you define the relationship between the tables in the ON clause and the search condition in the WHERE clause.

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